Add -o option to only use a specific source for an AS-SET or Route Set

.gitignore

@@ -0,0 +1,4 @@
+*\.o
+*\.log
+.deps
+.libs

README.md

@@ -27,10 +27,10 @@
 
 The
 **bgpq4**
-utility used to generate configurations (prefix-lists, extended
+utility is used to generate configurations (prefix-lists, extended
 access-lists, policy-statement terms and as-path lists) based on IRR data.
 
-The options are as follows:
+It's options are as follows:
 
 **-4**
 
@@ -162,7 +162,7 @@ The options are as follows:
 
 **-W** *len*
 
-> generate as-path strings of no more than len items (use 0 for inifinity).
+> generate as-path strings of no more than len items (use 0 for infinity).
 
 **-U**
 
@@ -342,28 +342,70 @@ be in one line (sometimes it makes sense):
 
 # NOTES ON SOURCES
 
-By default
-*bgpq4*
-trusts to data from all databases mirrored into NTT's IRR service.
-Unfortunately, not all these databases are equal in how much can we
-trust their data.
+By default *bgpq4* trusts data from all databases mirrored into NTT's IRR service.
+Unfortunately, not all these databases are equal in how much can we trust their 
+data.
 RIR maintained databases (AFRINIC, ARIN, APNIC, LACNIC and RIPE)
-shall be trusted more than the others because they are indeed have the
-knowledge about which address space allocated to this or that ASn,
-other databases lack this knowledge and can (and, actually, do) contain
-some stale data: noone but RIRs care to remove outdated route-objects
-when address space revoked from one ASn and allocated to another.
-In order to keep their filters both compact and actual,
-*bgpq4 users*
-are encouraged to use '-S' flag to limit database sources to only
-ones they trust.
+shall be trusted more than the others because they have the knowledge about 
+which address space is allocated to each ASN, other databases lack this 
+knowledge and can (and actually do) contain some stale data: nobody but RIRs 
+care to remove outdated route-objects when address space is revoked from one 
+ASN and allocated to another. In order to keep their filters both compact and 
+current, *bgpq4 users* are encouraged to use one of two method to limit 
+database sources to only ones they trust.
+
+One option is to use the '-S' flag. This limits all queries to a specific data 
+source. For example, the following command tells IIRd to only use data from 
+the RIPE RIR DB to build the prefix list for the AS-SET:
+
+	$./bgpq4 -S RIPE AS-VOSTRON
+	no ip prefix-list NN
+	ip prefix-list NN permit 89.21.224.0/19
+	ip prefix-list NN permit 134.0.64.0/21
+
+Be aware though, than an AS-SET may contain members from other data sources.
+In this case IRRd won't respond to the bgpq4 query will all the prefixes in the 
+AS-SET tree. Make sure to use the '-S' flag with all the data sources required 
+for the AS-SET being expanded:
+
+	$./bgpq4 -S RIPE,ARIN AS-VOSTRON
+	no ip prefix-list NN
+	ip prefix-list NN permit 89.21.224.0/19
+	ip prefix-list NN permit 134.0.64.0/21
+	ip prefix-list NN permit 208.86.232.0/24
+	ip prefix-list NN permit 208.86.233.0/24
+	ip prefix-list NN permit 208.86.234.0/24
+	ip prefix-list NN permit 208.86.235.0/24
+
+The other option is to specify a source for an AS-SET or Route Set using the 
+"::" notation. When bgpq4 detects this, it will look for "::" in the specified 
+AS-SET or RS on the CLI, and in all members of the AS-SET/RS, and for each 
+member with a data source specified in "::" format, it will set the IRRd data 
+source to the given value, query the AS-SET/RS, then reset the data sources back
+ to the default list for the next object in the tree.
+
+	$./bgpq4 RIPE::AS-VOSTRON
+	no ip prefix-list NN
+	ip prefix-list NN permit 89.21.224.0/19
+	ip prefix-list NN permit 134.0.64.0/21
+	ip prefix-list NN permit 208.86.232.0/22
+	ip prefix-list NN permit 208.86.232.0/24
+	ip prefix-list NN permit 208.86.233.0/24
+	ip prefix-list NN permit 208.86.234.0/24
+	ip prefix-list NN permit 208.86.235.0/24
+
+In comparison to the '-S' flag, this method return all the prefixes under the 
+AS-SET, but the root of the tree "AS-VOSTRON" was queries from RIPE only. None 
+of the member objects used the "::" notation so they were queries from the 
+default source list (which is all sources).
+
 
 General recommendations:
 
 Use minimal set of RIR databases (only those in which you and your
 customers have registered route-objects).
 
-Avoid using ARIN-NONAUTH and RIPE-NONAUTH as trusted source: these records
+Avoid using ARIN-NONAUTH and RIPE-NONAUTH as trusted sources: these records
 were created in database but for address space allocated to different RIR,
 so the NONAUTH databases have no chance to confirm validity of this route
 object.
@@ -380,6 +422,9 @@ object.
 	ip prefix-list NN permit 45.65.184.0/22
 	[...]
 
+When known, use the "::" notation to speicy the authortative data source for 
+an AS-SET or RS instead of the -S flag.
+
 # PERFORMANCE
 
 To improve \`bgpq4\` performance when expanding extra-large AS-SETs you
@@ -430,7 +475,7 @@ In order to create a distribution archive, run:
 When everything is OK,
 **bgpq4**
 generates access-list to standard output and exits with status == 0.
-In case of errors they are printed to stderr and program exits with
+In case of errors they are printed to stderr and the program exits with
 non-zero status.
 
 # AUTHORS